SCTs are very rare in adults, and as a rule these tumors are benign and have extremely low potential for malignancy. This estimation of potential is based on the idea that because the tumor existed for decades prior to diagnosis, without becoming malignant, it has little or no potential to ever become malignant. For this reason, and because coccygectomy in adults has greater risks than in babies, some surgeons prefer not to remove the coccyx of adult survivors of SCT. There are case reports of good outcomes.

For malignant teratomas, usually, surgery is followed by chemotherapy.

Teratomas that are in surgically inaccessible locations, or are very complex, or are likely to be malignant (due to late discovery and/or treatment) sometimes are treated first with chemotherapy.

Treatment for dermoid cyst is complete surgical removal, preferably in one piece and without any spillage of cyst contents. Marsupialization, a surgical technique often used to treat pilonidal cyst, is inappropriate for dermoid cyst due to the risk of malignancy.

The association of dermoid cysts with pregnancy has been increasingly reported. They usually present the dilemma of weighing the risks of surgery and anesthesia versus the risks of untreated adnexal mass. Most references state that it is more feasible to treat bilateral dermoid cysts of the ovaries discovered during pregnancy if they grow beyond 6 cm in diameter.

The treatment of choice is complete surgical removal ("i.e.," complete resection). Teratomas are normally well-encapsulated and non-invasive of surrounding tissues, hence they are relatively easy to resect from surrounding tissues. Exceptions include teratomas in the brain, and very large, complex teratomas that have pushed into and become interlaced with adjacent muscles and other structures.

Prevention of recurrence does not require "en bloc" resection of surrounding tissues.

Late effects are of two kinds: consequences of the tumor itself, and consequences of surgery and other treatments for the tumor.

Complications of not removing the coccyx may include both recurrence of the teratoma and metastatic cancer. Late malignancies usually involve incomplete excision of the coccyx and are adenocarcinoma.

Although functional disability in survivors is common, a small comparative study found a nonsignificant difference between SCT survivors and a matched control group.

In rare cases, pelvic scarring may necessitate that a pregnant woman who is a SCT survivor deliver her baby by Cesarean section.

A dermoid cyst is a teratoma of a cystic nature that contains an array of developmentally mature, solid tissues. It frequently consists of skin, hair follicles, and sweat glands, while other commonly found components include clumps of long hair, pockets of sebum, blood, fat, bone, nails, teeth, eyes, cartilage, and thyroid tissue.

As dermoid cysts grow slowly and contain mature tissue, this type of cystic teratoma is nearly always benign. In those rare cases wherein the dermoid cyst is malignant, a squamous cell carcinoma usually develops in adults, while infants and children usually present with an endodermal sinus tumor.

Most treatments involve some combination of surgery and chemotherapy. Treatment with cisplatin, etoposide, and bleomycin has been described.

Before modern chemotherapy, this type of neoplasm was highly lethal, but the prognosis has significantly improved since.

When endodermal sinus tumors are treated promptly with surgery and chemotherapy, fatal outcomes are exceedingly rare.

Although surgery is the treatment of choice, it must be preceded by imaging studies to exclude an intracranial connection. Potential complications include meningitis and a cerebrospinal fluid leak. Recurrences or more correctly persistence may be seen in up to 30% of patients if not completely excised.

Thoracocentesis, pericardiocentesis, pleurodesis, ligation of thoracic duct, pleuroperitoneal shunt, radiation therapy, pleurectomy, pericardial window, pericardiectomy, thalidomide, interferon alpha 2b, Total Parenteral Nutrition (TPN), medium chain triglyceride (MCT) and high protein diet, chemotherapy, sclerotherapy, transplant;

There is no standard approach to the treatment of lymphangiomatosis and treatment often is aimed at reducing symptoms. Surgical intervention may be indicated when complications arise and a number of reports of response to surgical interventions, medications, and dietary approaches can be found in the medical literature.

Unfortunately, there is no standardized treatment for lymphangiomatosis and no cure.

Treatment modalities that have been reported in the medical literature, by system, include:

Simple surgical excision is curative. The recommended treatment is that the skin is peeled off the extra-auricular tissue and protruding cartilage remnants are trimmed. Normal appearance is achieved in majority of cases. The reconstruction successful in true cases of accessory auricle, as it also is in individuals with auricular appendages.

Polyembryoma is a rare, very aggressive form of germ cell tumor usually found in the ovaries. Polyembryoma has features of both yolk sac tumour and undifferentiated teratoma/embryonal carcinoma, with a characteristic finding of embryoid bodies lying in a loose mesenchymal stroma.

It has been found in association with Klinefelter syndrome.

These lesions usually present in neonates, although they may not come to clinical attention until adulthood (for cosmetic reasons). There is no gender predilection. They are present in approximately 3-6 per 1000 live births.

Nasal glial heterotopia is rare, while an encephalocele is uncommon. NGH usually presents in infancy, while encephalocele may present in older children and adults. It is seen in both genders equally.

A struma ovarii (literally: goitre of the ovary) is a rare form of monodermal teratoma that contains mostly thyroid tissue, which may cause hyperthyroidism.

Despite its name, struma ovarii is not restricted to the ovary.

The vast majority of struma ovarii are benign tumors; however, malignant tumors of this type is found in a small percentage of cases.

Surgery is the mainstay of treatment for thymoma. If the tumor is apparently invasive and large, preoperative (neoadjuvant) chemotherapy and/or radiotherapy may be used to decrease the size and improve resectability, before surgery is attempted. When the tumor is an early stage (Masaoka I through IIB), no further therapy is necessary. Removal of the thymus in adults does not appear to induce immune deficiency. In children, however, postoperative immunity may be abnormal and vaccinations for several infectious agents are recommended. Invasive thymomas may require additional treatment with radiotherapy and chemotherapy (cyclophosphamide, doxorubicin and cisplatin).. Recurrences of thymoma are described in 10-30% of cases up to 10 years after surgical resection, and in the majority of cases also pleural recurrences can be removed. Recently, surgical removal of pleural recurrences can be followed by hyperthermic intrathoracic perfusion chemotherapy or Intrathoracic hyperthermic perfused chemotherapy (ITH).

Treatment may include antibiotic therapy, hot compresses and application of depilatory creams. In more severe cases, the cyst may need to be lanced or treated surgically. Lancing is performed using a local anesthesia, with healing time generally under one week. The most conservative surgical treatment, Bascom's Pit Picking procedure, is a relatively simple outpatient option that can be performed in a physician's office, involves minimal pain and requires only a few days healing. Although this procedure is much less invasive than the alternatives, it is not regularly practiced in the US. The Pit Picking procedure provides good results, fast recovery, and in instances where it is unsuccessful, other options for more invasive surgery can still be performed.

The more common course for surgical treatment is for the cyst to be surgically excised (along with pilonidal sinus tracts). Post-surgical wound packing may be necessary, and packing typically must be replaced once daily for 4 to 8 weeks. In some cases, two years may be required for complete granulation to occur. Sometimes the cyst is resolved via surgical marsupialization.

Surgeons can also excise the sinus and repair with a reconstructive flap technique, such as a "cleft lift" procedure or Z-plasty, usually done under general anesthetic. This approach is especially useful for complicated or recurring pilonidal disease, leaves little scar tissue and flattens the region between the buttocks, reducing the risk of recurrence. This approach typically results in a more rapid recovery than the traditional surgery, however there are fewer surgeons trained in the cleft lift procedure and thus, it may not be as accessible to patients, depending on their geographic location. Meta analysis shows recurrence rates were lower in open healing than with primary closure (RR 0.60, 95% CI 0.42 to 0.87) at the expense of time to healing. Pilonidal cysts recur and do so more frequently if the surgical wound is sutured in the midline, as opposed to away from the midline, which obliterates the natal cleft and removes the focus of shearing stress. An incision lateral to the intergluteal cleft is therefore preferred, especially given the poor healing of midline incisions in this region.

An attractive minimally invasive technique is to treat pilonidal sinus with fibrin glue. This technique is less painful than traditional excisional techniques and flaps, can be performed under local or general anaesthesia, does not require dressings or packing and allows return to normal activities within 1 to 2 days. Long term outcome and recurrence rates are not dissimilar to more invasive techniques in 5 year follow up in a small randomised controlled trial.

Fibrin glue has also been shown to be better than more invasive alternatives in the treatment of pilonidal sinus disease in children, where a quick return to normal activities and minimal postoperative pain are especially important.

A minimally invasive surgical technique, was developed in Israel by Moshe Gips et al.,2008. and is similar to the pit picking technique first described by Bascom in 1980 In this procedure, trephines or biopsy punches which only "core out" and remove the diseased tissue and cyst are used, leaving only small holes to heal. Work or school activities will be resumed in one or two days, without or with minimal postoperative pain. The two procedures have been successfully combined by L. Basso in Rome (Italy).

While the recovery rate is positive for most, some suffer long term effects. Recorded instances include patients with continued postoperative pain for years following the surgical procedure. Primary complaints included pain when sitting for long period of times or following abrasive contact with the lower back and buttocks.

If the tumor is found incidentally in an asymptomatic person, the treatment approach is controversial. Certainly a conservative approach is warranted in certain individuals. If the tumor is large and pedunculated, a case may be made for surgical excision prior to symptoms developing due to the higher risk of embolism. However, this is still considered controversial.

If the papillary fibroelastoma is associated with symptoms, surgical excision is generally recommended for relief of symptoms. A minimally invasive approach may be possible if the tumor involves the aortic valve or right atrium. In the case of aortic valve involvement, excision of the tumor is often valve-sparing, meaning that replacement of the valve with a prosthetic valve is not necessary. Repair of the native valve with a pericardial patch has been described.

An immature teratoma is a rare type of malignant (cancerous) germ cell tumor (type of tumor that begins in the cells that give rise to sperm or eggs).

Like a mature teratoma, it contains several different types of tissue such as hair, muscle, and bone. Unlike a mature teratoma, it contains primitive neuroepithelium.

Prognosis is much worse for stage III or IV thymomas as compared with stage I and II tumors. Invasive thymomas uncommonly can also metastasize, generally to pleura, bones, liver or brain in approximately 7% of cases. Patients with stage III and IV tumors may nonetheless survive for several years with appropriate oncological management.

Patients who have undergone thymectomy for thymoma should be warned of possible severe side effects after yellow fever vaccination. This is probably caused by inadequate T-cell response to live attenuated yellow fever vaccine. Deaths have been reported.

The strumal carcinoid is a type of monodermal teratoma with histomorphologic features of (1) the thyroid gland and (2) a neuroendocrine tumour (carcinoid).

MEM comprises a heterogeneous group of neoplasms believed to originate from the neural crest. First hints to this type of tumor were probably from Shuangshoti and Nestky (1971) and from Holimon and Rosenblum (1971) (2-3). Additional contributions were provided thereafter by Naka et al. (1975), Karcioglu et al. (1977), Cozzutto et al. (1982) and Kawamoto et al. (1987).

Kosem et al. collected 44 cases of MEM in a 2004 review and examined management data finding out that resection with pre- or post-surgery chemotherapy yielded the best results with one death only in 13. In the five cases reported by Mouton et al. an aggressive chemotherapy and adequate surgical excision granted a disease-free interval for 7 to 50 months. The attainability of radical surgical

ablation seems the most important prognostic factor (10).

A papillary fibroelastoma is a primary tumor of the heart that typically involves one of the valves of the heart. Papillary fibroelastomas, while considered generally rare, make up about 10 percent of all primary tumors of the heart. They are the third most common type of primary tumor of the heart, behind cardiac myxomas and cardiac lipomas.

Current treatment options include:

- Surgical debulking

- High-dose Corticosteroid therapy

- Cyclosporin

- Interferon-α

- Chemotherapy

- Vemurafenib. It would appear that approximately half these patients harbor point mutations of the BRAF gene at codon 600 substituting the amino acid glutamine for valine. Vemurafenib, an oral FDA approved targeted agent to the BRAF protein for melanoma, shows dramatic activity in patients Erdheim–Chester disease whose tumor contains the same mutation. In 2017 the US FDA approved vemurafenib for this indication.

- Radiation therapy

All current treatments have had varying degrees of success.

The vinca alkaloids and anthracyclines have been used most commonly in ECD treatment.

Ectomesenchymoma is a rare, fast-growing tumor of the nervous system or soft tissue that occurs mainly in children, although cases have been reported in patients up to age 60. Ectomesenchymomas may form in the head and neck, abdomen, perineum, scrotum, or limbs. Also called malignant ectomesenchymoma.

Malignant ectomesenchymoma (MEM) is a rare tumor of soft tissues or the CNS, which is composed of both neuroectodermal elements [represented by ganglion cells and/or well-differentiated or poorly differentiated neuroblastic cells such as ganglioneuroma, ganglioneuroblastoma, neuroblastoma, peripheral primitive neuroectodermal tumors – PNET] and one or more mesenchymal neoplastic elements, usually rhabdomyosarcoma . The most accepted theory suggests that this tumor arises from remnants of migratory neural crest cells and thus from the ectomesenchyme.